1. Field of the Invention
The invention concerns a two-chamber vessel useful as a fluid/solids treatment apparatus and more particularly to a single vessel having two chambers in which a fluid stream may be treated with particulate solids in parallel flow, i.e., through each of the two chambers concurrently; in series flow, i.e., through a first chamber and thereafter through a second chamber or through a second chamber and thereafter through a first chamber; or in alternating flow, i.e., where all of the fluid passes through a first chamber while solids in the second chamber are being regenerated or replaced. Distinctly different treating solids may be provided in the chamber compared to the other chamber.
2. Description of the Prior Art
Treatment of fluids (gases or liquids) with particulate solids is a process used in many technologies. Of particular interest is treatment of a fluid with particulate activated carbon for the purpose of removing selected ingredients, usually contaminants or pollutants, from the fluid.
Activated carbon is employed in particulate form, usually screened to typically plus 1/32 inch mesh, minus 3/8 inch mesh. A container is provided with an inventory of particulate activated carbon and the fluid (gas or liquid) is introduced into the container at one end and passes through the inventory of activated carbon particles which selectively adsorb the adsorbable ingredients of the fluid. The unadsorbed fluid is withdrawn from the container.
It is not uncommon to use activated carbon treatment containers in parallel and it is not uncommon to use activated carbon containers in series. Parallel installations are employed where there is a large volume of fluid which requires a predetermined residence time in contact with the activated carbon, a residence time which cannot be achieved in a single container. Serial arrangements are employed where a preliminary reduction in the contaminant content of the fluid undergoing treatment is achieved in the first container and a further reduction in contaminant content is achieved in the second container. A particular advantage of the serial or series arrangement is that the more saturated adsorbent is maintained in the upstream container and the less saturated adsorbent is in the downstream container, achieving countercurrent flow efficiency.
Another serial arrangement provides different treating solids in each chamber. For example, one chamber may contain sand and function as a filter; one chamber may contain ion-exchange resins for selective removal of anions or cations; or one chamber may contain activated carbon for selective removal of organic ingredients. It is commonplace to have more than two containers and to regenerate activated carbon which approaches its adsorption capacity. Regeneration sometimes occurs in situ. Ion exchange resins normally are regenerated in situ; sand as a filter may be backwashed in situ. It is commonplace to withdraw spent activated carbon from a container and replace fresh or off-site-regenerated activated carbon. Spent activated carbon may be regenerated or discarded.
There are many applications for activated carbon treatment of fluids in remote locations, e.g., chemical spills and chemical leaks, particularly gas leaks. In responding to such remote location applications, the operator frequently does not have fore knowledge of the volume of fluid to be treated or the concentration of the contaminant. In permanent installations, there may be a need for continuous fluid treatment requiring at least two separate containers to permit regeneration or replacement of the contents of one container while another container is serving the requirements of the installation.